r - 如何在 R 中按 Rollup 分组？ (像 SQL)

Question

我有一个数据集，我想执行类似 Group By Rollup 的操作，就像我们在 SQL 中对聚合值所做的那样。

下面是一个可重现的例子。我知道 aggregate 工作得很好，正如解释的那样 here但不适合我的情况。

year<- c('2016','2016','2016','2016','2017','2017','2017','2017')
month<- c('1','1','1','1','2','2','2','2')
region<- c('east','west','east','west','east','west','east','west')
sales<- c(100,200,300,400,200,400,600,800)
df<- data.frame(year,month,region,sales)
df


year month region sales
1 2016     1   east   100
2 2016     1   west   200
3 2016     1   east   300
4 2016     1   west   400
5 2017     2   east   200
6 2017     2   west   400
7 2017     2   east   600
8 2017     2   west   800

现在我想做的是聚合(按年-月-地区求和)并在现有数据框中添加新的聚合行 例如应该有两个额外的行，如下所示，聚合行的区域新名称为“USA”

year month region sales
1 2016     1   east   400
2 2016     1   west   600
3 2016     1    USA  1000
4 2017     2   east   800
5 2017     2   west  1200
6 2017     2    USA  2000

我已经找到了一种方法(如下)，但我非常确定存在针对此问题的最佳解决方案或比我的更好的解决方法

df1<- setNames(aggregate(df$sales, by=list(df$year,df$month, df$region), FUN=sum),
    c('year','month','region', 'sales'))


df2<- setNames(aggregate(df$sales, by=list(df$year,df$month), FUN=sum),
               c('year','month', 'sales'))

df2$region<- 'USA'                  ## added a new column- region- for total USA
df2<- df2[,  c('year','month','region', 'sales')]  ## reordering the columns of df2

df3<- rbind(df1,df2)

df3<- df3[order(df3$year,df3$month,df3$region),]  ## order by
rownames(df3)<- NULL  ## renumbered the rows after order by

df3

感谢支持!

Answer 1

reshape2包中的

melt/dcast可以做小计。运行 dcast 后，我们使用 zoo 包中的 na.locf 将月份列中的 "(all)" 替换为月份:

library(reshape2)
library(zoo)

m <- melt(df, measure.vars = "sales")
dout <- dcast(m, year + month + region ~ variable, fun.aggregate = sum, margins = "month")

dout$month <- na.locf(replace(dout$month, dout$month  == "(all)", NA))

给予:

> dout
  year month region sales
1 2016     1   east   400
2 2016     1   west   600
3 2016     1  (all)  1000
4 2017     2   east   800
5 2017     2   west  1200
6 2017     2  (all)  2000